 * {
     box-sizing: border-box;
     margin: 0;
     padding: 0;
 }

 #demo2 {
     display: none;
 }

 #demo {
     padding: 20px;
     position: fixed;
     height: 40vh;
     top: 0;
     left: 0px;
     width: 100%;
     border: 1px solid black;
     overflow-y: auto;
 }

 #demo::-webkit-scrollbar {
     display: none;
 }

 #html {
     position: fixed;
     bottom: 0;
     left: 0;
     width: 100%;
     height: 60vh;
     background-color: #ffe500;
 }

 #buttons {
     position: fixed;
     right: 0;
     top: 0;
     z-index: 10;
     display: flex;
     flex-direction: column;
     margin-top: 10px;
     margin-right: 10px;
 }

 #buttons>button {
     margin-bottom: 10px;
     padding: 4px 8px;
 }